Infants born with gastroschisis usually require surgery shortly after birth. After surgery the intestine is often unable to digest human milk or formula for weeks or months. During this time the baby has to remain in the hospital to receive special nutrition through an IV. How bacteria colonize the intestine in these babies is unknown. Probiotics are bacteria that appear to have beneficial effects on digestion. This study will test whether giving probiotic bacteria to babies after surgery for gastroschisis will change the bacteria in the intestine to be more like those of a healthy breast-fed baby.